Nonsteroidal selective androgen receptor modulator · Fact sheet
S-23
S-23 is an experimental SARM investigated in rat male-contraception research. A human metabolite-detection experiment does not establish efficacy or a safe regimen; reproductive suppression is a central concern.
What is S-23?
S-23 and S-22/enobosarm are different molecules.
Animal contraception experiments combined S-23 with estradiol benzoate; their results do not describe S-23 alone in people.
Benefits & claims
Interest includes performance or metabolic effects, but a mechanism, hormone change or lean-mass result does not establish safe improvement in athletic function.
What the evidence supports
- Rat experiments altered muscle, hormonal and reproductive measures.
- Reversible infertility in a particular rat protocol does not guarantee reversibility in humans.
- A detectable human exposure is not evidence of safe repeated use or established benefit.
Research areas
- Performance-related biology
- Clinical or preclinical disease research
Dosage & frequency
No established human regimenThe reviewed sources do not establish a human treatment amount or frequency for S-23. Animal and laboratory exposures are not human regimens.
How to read these amounts
An approved regimen belongs to a specific product, indication, and population. A study regimen describes what researchers tested; it does not establish a prescription or a safe self-use protocol. Products, routes, and formulations are not interchangeable. A prescriber uses the full label and individual clinical circumstances.
Personal accounts may describe amounts, schedules and outcomes beyond clinical research. They do not establish a regimen. Read the reported experiences
Formulations, interactions & practical context
- Identity and pharmacology
- S-23 and S-22/enobosarm are different molecules.Preclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception. In vitro characterization of S-23 metabolites produced by human liver microsomes, and subsequent application to urine after a controlled oral administration.
Formulation differences
- Animal contraception experiments combined S-23 with estradiol benzoate; their results do not describe S-23 alone in people.
Interactions & precautions
- The reviewed sources do not establish a comprehensive human interaction profile for this exact substance or combination.
What is still unresolved
- Long-term clinically meaningful benefit
- Endocrine, cardiovascular and organ safety
- Identity, exposure and interaction differences outside research settings
Side effects & risks
- Androgenic endocrine and fertility effects are directly relevant to the research rationale.
- Human long-term reproductive, liver and cardiovascular safety is unestablished; FDA class warnings remain relevant context.
This is a summary of the cited evidence, not a complete product label. A lack of human safety data does not establish safety.
Clinical research
Limited or unclear evidenceThe main efficacy work cited is in male rats. A separate human analytical study involved a single administration for metabolite detection, not therapeutic efficacy.
Studies
Rat contraception and tissue-response experiments, including estradiol co-treatment.
Single-volunteer human metabolite-detection experiment.
Personal experiences
Reports describe what someone noticed. They cannot establish cause, typical results, or how often a side effect happens. Amounts and schedules describe the individual account, not an effective or safe dose. Product identity and strength may be unverified, and missing details are left explicit.
No attributable personal accounts were found in the sources reviewed.
Approval status
S-23 has no FDA-approved therapeutic product. The cited research does not establish an approved performance-enhancement use.
Preclinical evidence; no FDA-approved product
Approval covers the labeled product, use and population. A trial phase does not establish success; a stopped program is not ongoing research.
- Preclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception.
- In vitro characterization of S-23 metabolites produced by human liver microsomes, and subsequent application to urine after a controlled oral administration.
- FDA: serious risks of SARM bodybuilding products
Open questions
- Long-term clinically meaningful benefit
- Endocrine, cardiovascular and organ safety
- Identity, exposure and interaction differences outside research settings
Summary
A detectable human exposure is not evidence of safe repeated use or established benefit.
Sources
Medical evidence and regulatory sources are listed here. Personal reports are linked separately in the experiences section.
- pubmedPreclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception.
Rat contraception and tissue-response experiments, including estradiol co-treatment.
- pubmedIn vitro characterization of S-23 metabolites produced by human liver microsomes, and subsequent application to urine after a controlled oral administration.
Single-volunteer human metabolite-detection experiment.
- fdaFDA: serious risks of SARM bodybuilding products
FDA class-level warning: unapproved products, liver injury and cardiovascular and hormone-associated risks; not a compound-specific incidence estimate.